1. Field of the Invention
This invention relates to an actuating means for a separator pawl which separates a recording sheet, such as recording paper, from tight contact with a photosensitive drum. More particularly, the present invention relates to an actuating means which is adapted to prevent the separator pawl from damaging the surface of a photosensitive drum when the photosensitive drum is mounted to or dismounted from an electrophotographic device.
2. Description of the Prior Art
Various procedures have been proposed and practiced for electrophotographic devices of the type in which a recording sheet such as recording paper is separated from a photosensitive drum after transferring a toner image formed on the surface of the photosensitive drum to the recording sheet in tight contact with the drum. The photosensitive drum of the electrophotographic device of the aforesaid type has to fulfill various functions, such as reliable separation of the recording sheet from the tight contact with the photosensitive drum, formation and transfer of copied image (toner picture) of high quality, ease of replacement, and so on.
A number of methods are known for separating the recording paper from the photosensitive drum, and of all the known methods those using a separator pawl are very reliable. In the method using the separator pawl, the reliable separation of the recording paper is ensured by providing a recess on that portion of the surface of the photosensitive drum where the separator pawl comes in contact therewith, so that the tip of the separator pawl enters the recess and comes in contact with the leading edge of the recording paper in tight contact with the photosensitive drum, the contact of the separator pawl with said recording paper being on the surface where the copied picture is transferred.
The service life of the photosensitive drum is shorter than those of other components of the electrophotographic device, so that the photosensitive drum is considered to be a consumable and comparatively frequent replacement of the photosensitive drum is necessary. In replacing the photosensitive drum with mechanisms of the prior art, the separator pawl and other peripheral elements of the photosensitive drum for the copying process are moved away from the photosensitive drum before starting the replacement.
In the aforesaid case of having the separator pawl disposed in the close proximity to the recess formed on the photosensitive drum, if the photosensitive drum is pulled out of the electrophotographic device before moving the pawl and other elements away from such photosensitive drum by mistake, both the surface of the photosensitive drum and the separator pawl are liable to damaged by scratching or the like. Thus, the separator pawl of the prior art has a shortcoming in that it has to be moved, possibly along with other peripheral elements disposed in the proximity of the photosensitive drum by separate steps which are different from the steps associated with the mounting and dismounting of the photosensitive drum, and such separate steps tend to make the replacement of the photosensitive drum cumbersome and complicated.